system

Does exactly the same thing as exec, except that a fork is
done first and the parent process waits for the child process to
exit. Note that argument processing varies depending on the
number of arguments. If there is more than one argument in LIST,
or if LIST is an array with more than one value, starts the program
given by the first element of the list with arguments given by the
rest of the list. If there is only one scalar argument, the argument
is checked for shell metacharacters, and if there are any, the
entire argument is passed to the system's command shell for parsing
(this is /bin/sh -c
on Unix platforms, but varies on other
platforms). If there are no shell metacharacters in the argument,
it is split into words and passed directly to execvp
, which is
more efficient. On Windows, only the systemPROGRAMLIST
syntax will
reliably avoid using the shell; systemLIST
, even with more than one
element, will fall back to the shell if the first spawn fails.

Perl will attempt to flush all files opened for
output before any operation that may do a fork, but this may not be
supported on some platforms (see perlport). To be safe, you may need
to set $ ($AUTOFLUSH
in English)
or call the autoflush
method of IO::Handle
on any open handles.

The return value is the exit status of the program as returned by the
wait call. To get the actual exit value, shift right by
eight (see below). See also exec. This is not what
you want to use to capture the output from a command; for that you
should use merely backticks or
qx//, as described in
`STRING` in perlop. Return value of -1 indicates a failure to start
the program or an error of the wait(2) system call (inspect
$! for the reason).

If you'd like to make system (and many other bits of
Perl) die on error, have a look at the autodie pragma.

Like exec, system allows you to lie
to a program about its name if you use the systemPROGRAMLIST
syntax. Again, see exec.

Since SIGINT
and SIGQUIT
are ignored during the execution of
system, if you expect your program to terminate on
receipt of these signals you will need to arrange to do so yourself
based on the return value.